The antidepressant fluoxetine alters food intake in cichlid fish

DORELLE, LUCIANA S.; DA CUÑA, R.; REY VÁZQUEZ, G.; GENOVESE, G.; LO NOSTRO F.

Buenos Aires

Congreso; 11th Biennial Meeting SETAC Latin America; 2015

SETAC

Pharmaceuticalsare commonly used to improve human and animal healthcare. These compounds areknown as ?emerging concern pollutants? since after their consumption andexcretion, they reach freshwater bodies as wastewater treatment plants areincapable of removing them, and could therefore affect non-target organisms.Among antidepressants, SSRIs -Serotonin Selective Reuptake Inhibitors- areprescribed for several psychiatric disorders, such as obsessive-compulsivedisorder and feeding alterations. In vertebrates, serotonin (5-HT) regulates behavior,humor, sexual impulse and appetite. Particularly, fluoxetine (FLX) is theactive ingredient of one of the most consumed SSRIs worldwide, Prozac®. Themain objective of this work was to evaluate the effect of FLX on the foodintake rate in Cichlasoma dimerus, a SouthAmerican freshwater fish who displays distinctive social hierarchies andagression patterns. Additionally, we analyzed the relationship between feeding,liver and brain serotonergic activity. Each fish received a dailyintraperitoneal (i.p.) or intramuscular (i.m.) injection for 5 days of saline0.6% (control group), 2 or 20 ug/g of FLX. Daily food intake was quantifiedthroughout the experiment. At the end of the experiment, levels of 5-HT and itsmetabolite 5-HIAA were determined in brain using HPLC-EC as a measure of brainserotonergic activity. Livers were weighed, fixed and processed for histology. Slideswere stained with Masson´s Trichromic and PAS techniques. Although no significantalterations were registered on brain serotonergic activity for neither i.p. nori.m. experiments, a tendency towards a dose-dependent increase was observed fori.m. In groups injected with 20 ug/g of FLX a marked decrease on food intakewas observed in both cases. This was associated with the presence of intenseacidophilia, lack of lipid reserves and marked area reduction of hepatocytes. Noalterations were observed in hepatosomatic index or body weight. These resultsmay indicate that FLX is producing an anorexigenic effect in C. dimerus adults, hence it could impactover reproductive physiology and behavior of this species, considering that aggressiveinteractions and the establishment of social hierarchies are pivotal forreproductive success.